1.2. Host Requirements

Hardware certification for Red Hat Virtualization is covered by the hardware certification for Red Hat Enterprise Linux. For more information, see https://access.redhat.com/solutions/725243. To confirm whether specific hardware items are certified for use with Red Hat Enterprise Linux, see https://access.redhat.com/ecosystem/#certifiedHardware.

For more information on the requirements and limitations that apply to guests see https://access.redhat.com/articles/rhel-limits and https://access.redhat.com/articles/906543.

1.2.1. CPU Requirements

All CPUs must have support for the Intel® 64 or AMD64 CPU extensions, and the AMD-V™ or Intel VT® hardware virtualization extensions enabled. Support for the No eXecute flag (NX) is also required.

The following CPU models are supported:

  • AMD

    • Opteron G1 (deprecated)
    • Opteron G2 (deprecated)
    • Opteron G3 (deprecated)
    • Opteron G4
    • Opteron G5
  • Intel

    • Conroe (deprecated)
    • Penryn (deprecated)
    • Nehalem
    • Westmere
    • Sandybridge
    • Haswell
    • Haswell-noTSX
    • Broadwell
    • Broadwell-noTSX
    • Skylake (client)
    • Skylake (server)
  • IBM POWER8

1.2.1.1. Checking if a Processor Supports the Required Flags

You must enable virtualization in the BIOS. Power off and reboot the host after this change to ensure that the change is applied.

  1. At the Red Hat Enterprise Linux or Red Hat Virtualization Host boot screen, press any key and select the Boot or Boot with serial console entry from the list.
  2. Press Tab to edit the kernel parameters for the selected option.
  3. Ensure there is a space after the last kernel parameter listed, and append the parameter rescue.
  4. Press Enter to boot into rescue mode.
  5. At the prompt, determine that your processor has the required extensions and that they are enabled by running this command:

    # grep -E 'svm|vmx' /proc/cpuinfo | grep nx

If any output is shown, the processor is hardware virtualization capable. If no output is shown, your processor may still support hardware virtualization; in some circumstances manufacturers disable the virtualization extensions in the BIOS. If you believe this to be the case, consult the system’s BIOS and the motherboard manual provided by the manufacturer.

1.2.2. Memory Requirements

The minimum required RAM is 2 GB. The maximum supported RAM is 2 TB.

However, the amount of RAM required varies depending on guest operating system requirements, guest application requirements, and guest memory activity and usage. KVM can also overcommit physical RAM for virtualized guests, allowing you to provision guests with RAM requirements greater than what is physically present, on the assumption that the guests are not all working concurrently at peak load. KVM does this by only allocating RAM for guests as required and shifting underutilized guests into swap.

1.2.3. Storage Requirements

Hosts require local storage to store configuration, logs, kernel dumps, and for use as swap space. The minimum storage requirements of Red Hat Virtualization Host are documented in this section. The storage requirements for Red Hat Enterprise Linux hosts vary based on the amount of disk space used by their existing configuration but are expected to be greater than those of Red Hat Virtualization Host.

The minimum storage requirements for host installation are listed below. However, Red Hat recommends using the default allocations, which use more storage space.

  • / (root) - 6 GB
  • /home - 1 GB
  • /tmp - 1 GB
  • /boot - 1 GB
  • /var - 15 GB
  • /var/log - 8 GB
  • /var/log/audit - 2 GB
  • swap - 1 GB (for the recommended swap size, see https://access.redhat.com/solutions/15244)
  • Anaconda reserves 20% of the thin pool size within the volume group for future metadata expansion. This is to prevent an out-of-the-box configuration from running out of space under normal usage conditions. Overprovisioning of thin pools during installation is also not supported.
  • Minimum Total - 45 GB

If you are also installing the RHV-M Appliance for self-hosted engine installation, /var/tmp must be at least 5 GB.

1.2.4. PCI Device Requirements

Hosts must have at least one network interface with a minimum bandwidth of 1 Gbps. Red Hat recommends that each host have two network interfaces, with one dedicated to supporting network-intensive activities, such as virtual machine migration. The performance of such operations is limited by the bandwidth available.

For information about how to use PCI Express and conventional PCI devices with Intel Q35-based virtual machines, see Using PCI Express and Conventional PCI Devices with the Q35 Virtual Machine.

1.2.5. Device Assignment Requirements

If you plan to implement device assignment and PCI passthrough so that a virtual machine can use a specific PCIe device from a host, ensure the following requirements are met:

  • CPU must support IOMMU (for example, VT-d or AMD-Vi). IBM POWER8 supports IOMMU by default.
  • Firmware must support IOMMU.
  • CPU root ports used must support ACS or ACS-equivalent capability.
  • PCIe devices must support ACS or ACS-equivalent capability.
  • Red Hat recommends that all PCIe switches and bridges between the PCIe device and the root port support ACS. For example, if a switch does not support ACS, all devices behind that switch share the same IOMMU group, and can only be assigned to the same virtual machine.
  • For GPU support, Red Hat Enterprise Linux 7 supports PCI device assignment of PCIe-based NVIDIA K-Series Quadro (model 2000 series or higher), GRID, and Tesla as non-VGA graphics devices. Currently up to two GPUs may be attached to a virtual machine in addition to one of the standard, emulated VGA interfaces. The emulated VGA is used for pre-boot and installation and the NVIDIA GPU takes over when the NVIDIA graphics drivers are loaded. Note that the NVIDIA Quadro 2000 is not supported, nor is the Quadro K420 card.

Check vendor specification and datasheets to confirm that your hardware meets these requirements. The lspci -v command can be used to print information for PCI devices already installed on a system.

1.2.6. vGPU Requirements

If you plan to configure a host to allow virtual machines on that host to install a vGPU, the following requirements must be met:

  • vGPU-compatible GPU
  • GPU-enabled host kernel
  • Installed GPU with correct drivers
  • Predefined mdev_type set to correspond with one of the mdev types supported by the device
  • vGPU-capable drivers installed on each host in the cluster
  • vGPU-supported virtual machine operating system with vGPU drivers installed